CA1172823A

CA1172823A - Space frames

Info

Publication number: CA1172823A
Application number: CA000403355A
Authority: CA
Inventors: Edwin T. Codd
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-05-20
Filing date: 1982-05-20
Publication date: 1984-08-21

Abstract

ABSTRACT
At each of the nodes of a double-layer flat grid space frame, the longitudinal chord members and the lateral chord members of both the upper grid and the lower grid are in superimposed crossing arrange-ment, the ends of the diagonal struts which interconnect the nodes of the upper and lower grids being interposed between longitudinal chord members and lateral chord members, a connector member being secured through the end of each diagonal strut extending from the node and through the chord members above and below it.

Description

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TITLE: "SPACE FRAMES"

BACKGROUND OF THE INVENTION
, 1. Field of the Invention This invention relates to space frames.

2. Brief Description of the Prior Art Space frames are well known and extensively used in the construction of buildings such as exhibition halls, theatres and the like where large areas are required to be covered, free of supporting colu~ms. For 1~ such purposes, architects commonly favour space frames of the double-layer flat grid type, such a structure having an upper square grid assembly of longitudinal and transverse chord members spaced above a lower square grid .
assembly of longitudinal and transverse chord members, intersections of the upper and lower grids being inter-connected by diagonal struts so that the space frame consists of a combination of square-base pyramidal shapes.
The economy or otherwise of space frames of th:is type is particularly sensitive to the cost of the nodal connections o~ the members comprising the yrid, and a variety o~ connector components have been clevised for interconnecting, at each node of the structure, the long-itudinal and lateral chord members and the diagonal struts.
An ideal jointing method should:
25 a) permit any required arrangement and number of - members at the joint, b) match the strength of the incoming members c) be compact, d) employ readily available materials suited to mass production, .

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e) be suitable ~or use with standard steel members, f) require little or no specialised techni~ue or equipment in fabrication, g) be simple to assemble, h) be compatable with other buildin~ materials, iJ be economical in the completed structure.

BRIEF SUMMAR~ OF THE INVENTION
The present invention has been devised with the general object of providing a space frame in which the node connections satisfy these requirements.
Accordingly, the invention resides broadly in a space frame of the type having an upper grid of longitudinal .. and lateral chord members, a lower grid of longitudinal and lateral chord members, and diagonal struts interconnecting ~: 15 nodes at chord intersections of the two grids, wherein at ~ each node one chord member overlies the other, an end of .. each strut extending ~rom the node is interpose~ between the said chord members, the said strut ends beiny in adjacent non-superimposed relationsllip, and each orle of the said strut ends is individually secured by a connector member passed through the said strut end and through the chord members above and below the said strut end. Preferably the longitudinal chord members and lateral chord members of each grid are channel sections oppositely arranged so that 25 their webs are towards each other.
BRIEF DESCRIPTION OF THE DRAWINGS
:
In the drawings:-FIGS. 1 and 2 are diagrammatic plan and elevation views respectively of a section of a flat double-layer space frame, ~,3 FIG. 3 is a perspective view of par-t o~ the space frame encircled at 3 in FIG. 1, FIG. 4 is a plan view of the parts shown in FIG. 3, and FIG. 5 is a per~pective view of the parts of the space frame encircled at 5 in FIG. 1.
DETAILED DESCRIPTION OF T~IE PREF~RRED EMBODIMENT
-The double-layer flat grid space frame illustrated is built up of longitudinal chord members 10 and lateral chord members 11 interconnected to form an upper square grid; longitudinal chord members 12 and la-teral chord members 13 interconnected to form a lower square grid;
and web diagonals or s-truts 14 fixed between the upper and lower grids. i All of the chord members 10, 11, 12 and 13 are of fairly llght gauge channel sections, their parallel flanges 15 having edge portions 16 turned through right angles towards each other, the channels of the l.ongit-udinal and lateral chord members of each of the upper and lower yrid~ belng oppos:i.tel~ d:Lrected so that the webs 17 of the crossing members are towards each other.
~ach of the diagonal struts 14 is of fairly light gauge steel tube, having both end portions flattened, as indicated at 18, the two flat-tened ends being bent, in opposite directions, through an acute angle to the axis of the main unflattened part of the strut, so that the two flattened end portions 18 are parallel. Both sides of each flattened end portion 18 are mitred, as shown in FIG. 4, to meet, at an e~tremity of the strut, at a right angle.
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' At each intersection in the upper grid of long-~- ikudinal and lateral chord members 10 and 11 (see FIG.
5) and at each lower grid in-tersection o~ longitudinal and lateral chord members 12 and 13 (see FIGS. 3 and 4), the two crossing members have the flattened ends 18 of four diagonal struts 14 interposed adjacently between tnemr four bolts 19 making a secure connection at the node 20. Each of the bolts l9 passes -through register-ing bolt holes in the longitudinal chord member, one of the interposed strut ~lattened end, and the lateral chord members. As shown in FIG. 4, the abu-tting mitred edges of adjacent strut end portions assist in imparting rigidity to the nodal connection.
At each node 20 of the lower grid, at the peri-phery of the grid, the connection between these twomembers and four diagonal struts is made similarly with four bolts.
At each of the corners of the wpper cJri~ a single strut 14 is connected to the junction of a long-itudinal chord member and a lateral chord member, andat the other peripheral junctions of longitudinal and lateral chord members in the upper grid, two diagonal strut members 14 have their ends secured. In each of these junctions, four of the bolts 19 are used r any suitable washers or like spacers (not shown) being used if desired where no strut is interposed between the chord members.
Chord members of other than the channel section illustrated may be used, for example chord members of "top-hat" section, or angle members; and angle-iron members, for example, may be used for the diagonal struts, their ends being appropriately shaped for inter-position and bolting between crossing chord . members.
A chord member may consist of two co-join~d parts, as shown in FIGS. 3 and 4, where the lateral chord member 13 is composed of two parts joined at the node in correct lineal alignment, each of the two parts being secured to the longitudinal chord member 12 by two of the bolts 19.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A space frame of the type having an upper grid of longitudinal chord members and lateral chord members, a lower grid of longitudinal chord members and lateral chord members, and diagonal struts interconnecting nodes at chord inter-sections of the two grids, characterized in that at each node:
one chord member overlies the other, an end of each strut extending from the node is interposed between the said chord members, the said strut ends being in adjacent, non-superimposed, relationship, and each one of the said strut ends is individually secured by a connector member passed through the said strut end and through the chord members above and below the said strut end.

2. A space frame according to Claim 1 and further characterized in that:
the longitudinal chord members and lateral chord members of each grid are channel sections oppositely arranged so that their webs are towards each other.

3. A space frame according to Claim 1 or Claim 2 and further characterized in that:
each of the diagonal struts is a tube with its ends flattened, and the two flattened ends are substantially parallel, being bent in opposite directions through similar angles.

4. A space frame according to Claim 1 or 2 wherein:
each of the said strut ends is formed with mitred side edges, and side edges of adjacent strut ends abut to prevent turning of the struts about the connector members.